git-clone: Rename --use-immingled-remote option to --no-separate-remote
[git] / builtin-blame.c
1 /*
2  * Pickaxe
3  *
4  * Copyright (c) 2006, Junio C Hamano
5  */
6
7 #include "cache.h"
8 #include "builtin.h"
9 #include "blob.h"
10 #include "commit.h"
11 #include "tag.h"
12 #include "tree-walk.h"
13 #include "diff.h"
14 #include "diffcore.h"
15 #include "revision.h"
16 #include "xdiff-interface.h"
17
18 #include <time.h>
19 #include <sys/time.h>
20 #include <regex.h>
21
22 static char blame_usage[] =
23 "git-blame [-c] [-l] [-t] [-f] [-n] [-p] [-L n,m] [-S <revs-file>] [-M] [-C] [-C] [commit] [--] file\n"
24 "  -c, --compatibility Use the same output mode as git-annotate (Default: off)\n"
25 "  -l, --long          Show long commit SHA1 (Default: off)\n"
26 "  -t, --time          Show raw timestamp (Default: off)\n"
27 "  -f, --show-name     Show original filename (Default: auto)\n"
28 "  -n, --show-number   Show original linenumber (Default: off)\n"
29 "  -p, --porcelain     Show in a format designed for machine consumption\n"
30 "  -L n,m              Process only line range n,m, counting from 1\n"
31 "  -M, -C              Find line movements within and across files\n"
32 "  -S revs-file        Use revisions from revs-file instead of calling git-rev-list\n";
33
34 static int longest_file;
35 static int longest_author;
36 static int max_orig_digits;
37 static int max_digits;
38 static int max_score_digits;
39
40 #ifndef DEBUG
41 #define DEBUG 0
42 #endif
43
44 /* stats */
45 static int num_read_blob;
46 static int num_get_patch;
47 static int num_commits;
48
49 #define PICKAXE_BLAME_MOVE              01
50 #define PICKAXE_BLAME_COPY              02
51 #define PICKAXE_BLAME_COPY_HARDER       04
52
53 /*
54  * blame for a blame_entry with score lower than these thresholds
55  * is not passed to the parent using move/copy logic.
56  */
57 static unsigned blame_move_score;
58 static unsigned blame_copy_score;
59 #define BLAME_DEFAULT_MOVE_SCORE        20
60 #define BLAME_DEFAULT_COPY_SCORE        40
61
62 /* bits #0..7 in revision.h, #8..11 used for merge_bases() in commit.c */
63 #define METAINFO_SHOWN          (1u<<12)
64 #define MORE_THAN_ONE_PATH      (1u<<13)
65
66 /*
67  * One blob in a commit that is being suspected
68  */
69 struct origin {
70         int refcnt;
71         struct commit *commit;
72         mmfile_t file;
73         unsigned char blob_sha1[20];
74         char path[FLEX_ARRAY];
75 };
76
77 static char *fill_origin_blob(struct origin *o, mmfile_t *file)
78 {
79         if (!o->file.ptr) {
80                 char type[10];
81                 num_read_blob++;
82                 file->ptr = read_sha1_file(o->blob_sha1, type,
83                                            (unsigned long *)(&(file->size)));
84                 o->file = *file;
85         }
86         else
87                 *file = o->file;
88         return file->ptr;
89 }
90
91 static inline struct origin *origin_incref(struct origin *o)
92 {
93         if (o)
94                 o->refcnt++;
95         return o;
96 }
97
98 static void origin_decref(struct origin *o)
99 {
100         if (o && --o->refcnt <= 0) {
101                 if (o->file.ptr)
102                         free(o->file.ptr);
103                 memset(o, 0, sizeof(*o));
104                 free(o);
105         }
106 }
107
108 struct blame_entry {
109         struct blame_entry *prev;
110         struct blame_entry *next;
111
112         /* the first line of this group in the final image;
113          * internally all line numbers are 0 based.
114          */
115         int lno;
116
117         /* how many lines this group has */
118         int num_lines;
119
120         /* the commit that introduced this group into the final image */
121         struct origin *suspect;
122
123         /* true if the suspect is truly guilty; false while we have not
124          * checked if the group came from one of its parents.
125          */
126         char guilty;
127
128         /* the line number of the first line of this group in the
129          * suspect's file; internally all line numbers are 0 based.
130          */
131         int s_lno;
132
133         /* how significant this entry is -- cached to avoid
134          * scanning the lines over and over
135          */
136         unsigned score;
137 };
138
139 struct scoreboard {
140         /* the final commit (i.e. where we started digging from) */
141         struct commit *final;
142
143         const char *path;
144
145         /* the contents in the final; pointed into by buf pointers of
146          * blame_entries
147          */
148         const char *final_buf;
149         unsigned long final_buf_size;
150
151         /* linked list of blames */
152         struct blame_entry *ent;
153
154         /* look-up a line in the final buffer */
155         int num_lines;
156         int *lineno;
157 };
158
159 static int cmp_suspect(struct origin *a, struct origin *b)
160 {
161         int cmp = hashcmp(a->commit->object.sha1, b->commit->object.sha1);
162         if (cmp)
163                 return cmp;
164         return strcmp(a->path, b->path);
165 }
166
167 #define cmp_suspect(a, b) ( ((a)==(b)) ? 0 : cmp_suspect(a,b) )
168
169 static void sanity_check_refcnt(struct scoreboard *);
170
171 static void coalesce(struct scoreboard *sb)
172 {
173         struct blame_entry *ent, *next;
174
175         for (ent = sb->ent; ent && (next = ent->next); ent = next) {
176                 if (!cmp_suspect(ent->suspect, next->suspect) &&
177                     ent->guilty == next->guilty &&
178                     ent->s_lno + ent->num_lines == next->s_lno) {
179                         ent->num_lines += next->num_lines;
180                         ent->next = next->next;
181                         if (ent->next)
182                                 ent->next->prev = ent;
183                         origin_decref(next->suspect);
184                         free(next);
185                         ent->score = 0;
186                         next = ent; /* again */
187                 }
188         }
189
190         if (DEBUG) /* sanity */
191                 sanity_check_refcnt(sb);
192 }
193
194 static struct origin *make_origin(struct commit *commit, const char *path)
195 {
196         struct origin *o;
197         o = xcalloc(1, sizeof(*o) + strlen(path) + 1);
198         o->commit = commit;
199         o->refcnt = 1;
200         strcpy(o->path, path);
201         return o;
202 }
203
204 static struct origin *get_origin(struct scoreboard *sb,
205                                  struct commit *commit,
206                                  const char *path)
207 {
208         struct blame_entry *e;
209
210         for (e = sb->ent; e; e = e->next) {
211                 if (e->suspect->commit == commit &&
212                     !strcmp(e->suspect->path, path))
213                         return origin_incref(e->suspect);
214         }
215         return make_origin(commit, path);
216 }
217
218 static int fill_blob_sha1(struct origin *origin)
219 {
220         unsigned mode;
221         char type[10];
222
223         if (!is_null_sha1(origin->blob_sha1))
224                 return 0;
225         if (get_tree_entry(origin->commit->object.sha1,
226                            origin->path,
227                            origin->blob_sha1, &mode))
228                 goto error_out;
229         if (sha1_object_info(origin->blob_sha1, type, NULL) ||
230             strcmp(type, blob_type))
231                 goto error_out;
232         return 0;
233  error_out:
234         hashclr(origin->blob_sha1);
235         return -1;
236 }
237
238 static struct origin *find_origin(struct scoreboard *sb,
239                                   struct commit *parent,
240                                   struct origin *origin)
241 {
242         struct origin *porigin = NULL;
243         struct diff_options diff_opts;
244         const char *paths[2];
245
246         if (parent->util) {
247                 /* This is a freestanding copy of origin and not
248                  * refcounted.
249                  */
250                 struct origin *cached = parent->util;
251                 if (!strcmp(cached->path, origin->path)) {
252                         porigin = get_origin(sb, parent, cached->path);
253                         if (porigin->refcnt == 1)
254                                 hashcpy(porigin->blob_sha1, cached->blob_sha1);
255                         return porigin;
256                 }
257                 /* otherwise it was not very useful; free it */
258                 free(parent->util);
259                 parent->util = NULL;
260         }
261
262         /* See if the origin->path is different between parent
263          * and origin first.  Most of the time they are the
264          * same and diff-tree is fairly efficient about this.
265          */
266         diff_setup(&diff_opts);
267         diff_opts.recursive = 1;
268         diff_opts.detect_rename = 0;
269         diff_opts.output_format = DIFF_FORMAT_NO_OUTPUT;
270         paths[0] = origin->path;
271         paths[1] = NULL;
272
273         diff_tree_setup_paths(paths, &diff_opts);
274         if (diff_setup_done(&diff_opts) < 0)
275                 die("diff-setup");
276         diff_tree_sha1(parent->tree->object.sha1,
277                        origin->commit->tree->object.sha1,
278                        "", &diff_opts);
279         diffcore_std(&diff_opts);
280
281         /* It is either one entry that says "modified", or "created",
282          * or nothing.
283          */
284         if (!diff_queued_diff.nr) {
285                 /* The path is the same as parent */
286                 porigin = get_origin(sb, parent, origin->path);
287                 hashcpy(porigin->blob_sha1, origin->blob_sha1);
288         }
289         else if (diff_queued_diff.nr != 1)
290                 die("internal error in blame::find_origin");
291         else {
292                 struct diff_filepair *p = diff_queued_diff.queue[0];
293                 switch (p->status) {
294                 default:
295                         die("internal error in blame::find_origin (%c)",
296                             p->status);
297                 case 'M':
298                         porigin = get_origin(sb, parent, origin->path);
299                         hashcpy(porigin->blob_sha1, p->one->sha1);
300                         break;
301                 case 'A':
302                 case 'T':
303                         /* Did not exist in parent, or type changed */
304                         break;
305                 }
306         }
307         diff_flush(&diff_opts);
308         if (porigin) {
309                 struct origin *cached;
310                 cached = make_origin(porigin->commit, porigin->path);
311                 hashcpy(cached->blob_sha1, porigin->blob_sha1);
312                 parent->util = cached;
313         }
314         return porigin;
315 }
316
317 static struct origin *find_rename(struct scoreboard *sb,
318                                   struct commit *parent,
319                                   struct origin *origin)
320 {
321         struct origin *porigin = NULL;
322         struct diff_options diff_opts;
323         int i;
324         const char *paths[2];
325
326         diff_setup(&diff_opts);
327         diff_opts.recursive = 1;
328         diff_opts.detect_rename = DIFF_DETECT_RENAME;
329         diff_opts.output_format = DIFF_FORMAT_NO_OUTPUT;
330         diff_opts.single_follow = origin->path;
331         paths[0] = NULL;
332         diff_tree_setup_paths(paths, &diff_opts);
333         if (diff_setup_done(&diff_opts) < 0)
334                 die("diff-setup");
335         diff_tree_sha1(parent->tree->object.sha1,
336                        origin->commit->tree->object.sha1,
337                        "", &diff_opts);
338         diffcore_std(&diff_opts);
339
340         for (i = 0; i < diff_queued_diff.nr; i++) {
341                 struct diff_filepair *p = diff_queued_diff.queue[i];
342                 if ((p->status == 'R' || p->status == 'C') &&
343                     !strcmp(p->two->path, origin->path)) {
344                         porigin = get_origin(sb, parent, p->one->path);
345                         hashcpy(porigin->blob_sha1, p->one->sha1);
346                         break;
347                 }
348         }
349         diff_flush(&diff_opts);
350         return porigin;
351 }
352
353 struct chunk {
354         /* line number in postimage; up to but not including this
355          * line is the same as preimage
356          */
357         int same;
358
359         /* preimage line number after this chunk */
360         int p_next;
361
362         /* postimage line number after this chunk */
363         int t_next;
364 };
365
366 struct patch {
367         struct chunk *chunks;
368         int num;
369 };
370
371 struct blame_diff_state {
372         struct xdiff_emit_state xm;
373         struct patch *ret;
374         unsigned hunk_post_context;
375         unsigned hunk_in_pre_context : 1;
376 };
377
378 static void process_u_diff(void *state_, char *line, unsigned long len)
379 {
380         struct blame_diff_state *state = state_;
381         struct chunk *chunk;
382         int off1, off2, len1, len2, num;
383
384         num = state->ret->num;
385         if (len < 4 || line[0] != '@' || line[1] != '@') {
386                 if (state->hunk_in_pre_context && line[0] == ' ')
387                         state->ret->chunks[num - 1].same++;
388                 else {
389                         state->hunk_in_pre_context = 0;
390                         if (line[0] == ' ')
391                                 state->hunk_post_context++;
392                         else
393                                 state->hunk_post_context = 0;
394                 }
395                 return;
396         }
397
398         if (num && state->hunk_post_context) {
399                 chunk = &state->ret->chunks[num - 1];
400                 chunk->p_next -= state->hunk_post_context;
401                 chunk->t_next -= state->hunk_post_context;
402         }
403         state->ret->num = ++num;
404         state->ret->chunks = xrealloc(state->ret->chunks,
405                                       sizeof(struct chunk) * num);
406         chunk = &state->ret->chunks[num - 1];
407         if (parse_hunk_header(line, len, &off1, &len1, &off2, &len2)) {
408                 state->ret->num--;
409                 return;
410         }
411
412         /* Line numbers in patch output are one based. */
413         off1--;
414         off2--;
415
416         chunk->same = len2 ? off2 : (off2 + 1);
417
418         chunk->p_next = off1 + (len1 ? len1 : 1);
419         chunk->t_next = chunk->same + len2;
420         state->hunk_in_pre_context = 1;
421         state->hunk_post_context = 0;
422 }
423
424 static struct patch *compare_buffer(mmfile_t *file_p, mmfile_t *file_o,
425                                     int context)
426 {
427         struct blame_diff_state state;
428         xpparam_t xpp;
429         xdemitconf_t xecfg;
430         xdemitcb_t ecb;
431
432         xpp.flags = XDF_NEED_MINIMAL;
433         xecfg.ctxlen = context;
434         xecfg.flags = 0;
435         ecb.outf = xdiff_outf;
436         ecb.priv = &state;
437         memset(&state, 0, sizeof(state));
438         state.xm.consume = process_u_diff;
439         state.ret = xmalloc(sizeof(struct patch));
440         state.ret->chunks = NULL;
441         state.ret->num = 0;
442
443         xdl_diff(file_p, file_o, &xpp, &xecfg, &ecb);
444
445         if (state.ret->num) {
446                 struct chunk *chunk;
447                 chunk = &state.ret->chunks[state.ret->num - 1];
448                 chunk->p_next -= state.hunk_post_context;
449                 chunk->t_next -= state.hunk_post_context;
450         }
451         return state.ret;
452 }
453
454 static struct patch *get_patch(struct origin *parent, struct origin *origin)
455 {
456         mmfile_t file_p, file_o;
457         struct patch *patch;
458
459         fill_origin_blob(parent, &file_p);
460         fill_origin_blob(origin, &file_o);
461         if (!file_p.ptr || !file_o.ptr)
462                 return NULL;
463         patch = compare_buffer(&file_p, &file_o, 0);
464         num_get_patch++;
465         return patch;
466 }
467
468 static void free_patch(struct patch *p)
469 {
470         free(p->chunks);
471         free(p);
472 }
473
474 static void add_blame_entry(struct scoreboard *sb, struct blame_entry *e)
475 {
476         struct blame_entry *ent, *prev = NULL;
477
478         origin_incref(e->suspect);
479
480         for (ent = sb->ent; ent && ent->lno < e->lno; ent = ent->next)
481                 prev = ent;
482
483         /* prev, if not NULL, is the last one that is below e */
484         e->prev = prev;
485         if (prev) {
486                 e->next = prev->next;
487                 prev->next = e;
488         }
489         else {
490                 e->next = sb->ent;
491                 sb->ent = e;
492         }
493         if (e->next)
494                 e->next->prev = e;
495 }
496
497 static void dup_entry(struct blame_entry *dst, struct blame_entry *src)
498 {
499         struct blame_entry *p, *n;
500
501         p = dst->prev;
502         n = dst->next;
503         origin_incref(src->suspect);
504         origin_decref(dst->suspect);
505         memcpy(dst, src, sizeof(*src));
506         dst->prev = p;
507         dst->next = n;
508         dst->score = 0;
509 }
510
511 static const char *nth_line(struct scoreboard *sb, int lno)
512 {
513         return sb->final_buf + sb->lineno[lno];
514 }
515
516 static void split_overlap(struct blame_entry *split,
517                           struct blame_entry *e,
518                           int tlno, int plno, int same,
519                           struct origin *parent)
520 {
521         /* it is known that lines between tlno to same came from
522          * parent, and e has an overlap with that range.  it also is
523          * known that parent's line plno corresponds to e's line tlno.
524          *
525          *                <---- e ----->
526          *                   <------>
527          *                   <------------>
528          *             <------------>
529          *             <------------------>
530          *
531          * Potentially we need to split e into three parts; before
532          * this chunk, the chunk to be blamed for parent, and after
533          * that portion.
534          */
535         int chunk_end_lno;
536         memset(split, 0, sizeof(struct blame_entry [3]));
537
538         if (e->s_lno < tlno) {
539                 /* there is a pre-chunk part not blamed on parent */
540                 split[0].suspect = origin_incref(e->suspect);
541                 split[0].lno = e->lno;
542                 split[0].s_lno = e->s_lno;
543                 split[0].num_lines = tlno - e->s_lno;
544                 split[1].lno = e->lno + tlno - e->s_lno;
545                 split[1].s_lno = plno;
546         }
547         else {
548                 split[1].lno = e->lno;
549                 split[1].s_lno = plno + (e->s_lno - tlno);
550         }
551
552         if (same < e->s_lno + e->num_lines) {
553                 /* there is a post-chunk part not blamed on parent */
554                 split[2].suspect = origin_incref(e->suspect);
555                 split[2].lno = e->lno + (same - e->s_lno);
556                 split[2].s_lno = e->s_lno + (same - e->s_lno);
557                 split[2].num_lines = e->s_lno + e->num_lines - same;
558                 chunk_end_lno = split[2].lno;
559         }
560         else
561                 chunk_end_lno = e->lno + e->num_lines;
562         split[1].num_lines = chunk_end_lno - split[1].lno;
563
564         if (split[1].num_lines < 1)
565                 return;
566         split[1].suspect = origin_incref(parent);
567 }
568
569 static void split_blame(struct scoreboard *sb,
570                         struct blame_entry *split,
571                         struct blame_entry *e)
572 {
573         struct blame_entry *new_entry;
574
575         if (split[0].suspect && split[2].suspect) {
576                 /* we need to split e into two and add another for parent */
577                 dup_entry(e, &split[0]);
578
579                 new_entry = xmalloc(sizeof(*new_entry));
580                 memcpy(new_entry, &(split[2]), sizeof(struct blame_entry));
581                 add_blame_entry(sb, new_entry);
582
583                 new_entry = xmalloc(sizeof(*new_entry));
584                 memcpy(new_entry, &(split[1]), sizeof(struct blame_entry));
585                 add_blame_entry(sb, new_entry);
586         }
587         else if (!split[0].suspect && !split[2].suspect)
588                 /* parent covers the entire area */
589                 dup_entry(e, &split[1]);
590         else if (split[0].suspect) {
591                 dup_entry(e, &split[0]);
592
593                 new_entry = xmalloc(sizeof(*new_entry));
594                 memcpy(new_entry, &(split[1]), sizeof(struct blame_entry));
595                 add_blame_entry(sb, new_entry);
596         }
597         else {
598                 dup_entry(e, &split[1]);
599
600                 new_entry = xmalloc(sizeof(*new_entry));
601                 memcpy(new_entry, &(split[2]), sizeof(struct blame_entry));
602                 add_blame_entry(sb, new_entry);
603         }
604
605         if (DEBUG) { /* sanity */
606                 struct blame_entry *ent;
607                 int lno = sb->ent->lno, corrupt = 0;
608
609                 for (ent = sb->ent; ent; ent = ent->next) {
610                         if (lno != ent->lno)
611                                 corrupt = 1;
612                         if (ent->s_lno < 0)
613                                 corrupt = 1;
614                         lno += ent->num_lines;
615                 }
616                 if (corrupt) {
617                         lno = sb->ent->lno;
618                         for (ent = sb->ent; ent; ent = ent->next) {
619                                 printf("L %8d l %8d n %8d\n",
620                                        lno, ent->lno, ent->num_lines);
621                                 lno = ent->lno + ent->num_lines;
622                         }
623                         die("oops");
624                 }
625         }
626 }
627
628 static void decref_split(struct blame_entry *split)
629 {
630         int i;
631
632         for (i = 0; i < 3; i++)
633                 origin_decref(split[i].suspect);
634 }
635
636 static void blame_overlap(struct scoreboard *sb, struct blame_entry *e,
637                           int tlno, int plno, int same,
638                           struct origin *parent)
639 {
640         struct blame_entry split[3];
641
642         split_overlap(split, e, tlno, plno, same, parent);
643         if (split[1].suspect)
644                 split_blame(sb, split, e);
645         decref_split(split);
646 }
647
648 static int find_last_in_target(struct scoreboard *sb, struct origin *target)
649 {
650         struct blame_entry *e;
651         int last_in_target = -1;
652
653         for (e = sb->ent; e; e = e->next) {
654                 if (e->guilty || cmp_suspect(e->suspect, target))
655                         continue;
656                 if (last_in_target < e->s_lno + e->num_lines)
657                         last_in_target = e->s_lno + e->num_lines;
658         }
659         return last_in_target;
660 }
661
662 static void blame_chunk(struct scoreboard *sb,
663                         int tlno, int plno, int same,
664                         struct origin *target, struct origin *parent)
665 {
666         struct blame_entry *e;
667
668         for (e = sb->ent; e; e = e->next) {
669                 if (e->guilty || cmp_suspect(e->suspect, target))
670                         continue;
671                 if (same <= e->s_lno)
672                         continue;
673                 if (tlno < e->s_lno + e->num_lines)
674                         blame_overlap(sb, e, tlno, plno, same, parent);
675         }
676 }
677
678 static int pass_blame_to_parent(struct scoreboard *sb,
679                                 struct origin *target,
680                                 struct origin *parent)
681 {
682         int i, last_in_target, plno, tlno;
683         struct patch *patch;
684
685         last_in_target = find_last_in_target(sb, target);
686         if (last_in_target < 0)
687                 return 1; /* nothing remains for this target */
688
689         patch = get_patch(parent, target);
690         plno = tlno = 0;
691         for (i = 0; i < patch->num; i++) {
692                 struct chunk *chunk = &patch->chunks[i];
693
694                 blame_chunk(sb, tlno, plno, chunk->same, target, parent);
695                 plno = chunk->p_next;
696                 tlno = chunk->t_next;
697         }
698         /* rest (i.e. anything above tlno) are the same as parent */
699         blame_chunk(sb, tlno, plno, last_in_target, target, parent);
700
701         free_patch(patch);
702         return 0;
703 }
704
705 static unsigned ent_score(struct scoreboard *sb, struct blame_entry *e)
706 {
707         unsigned score;
708         const char *cp, *ep;
709
710         if (e->score)
711                 return e->score;
712
713         score = 1;
714         cp = nth_line(sb, e->lno);
715         ep = nth_line(sb, e->lno + e->num_lines);
716         while (cp < ep) {
717                 unsigned ch = *((unsigned char *)cp);
718                 if (isalnum(ch))
719                         score++;
720                 cp++;
721         }
722         e->score = score;
723         return score;
724 }
725
726 static void copy_split_if_better(struct scoreboard *sb,
727                                  struct blame_entry *best_so_far,
728                                  struct blame_entry *this)
729 {
730         int i;
731
732         if (!this[1].suspect)
733                 return;
734         if (best_so_far[1].suspect) {
735                 if (ent_score(sb, &this[1]) < ent_score(sb, &best_so_far[1]))
736                         return;
737         }
738
739         for (i = 0; i < 3; i++)
740                 origin_incref(this[i].suspect);
741         decref_split(best_so_far);
742         memcpy(best_so_far, this, sizeof(struct blame_entry [3]));
743 }
744
745 static void find_copy_in_blob(struct scoreboard *sb,
746                               struct blame_entry *ent,
747                               struct origin *parent,
748                               struct blame_entry *split,
749                               mmfile_t *file_p)
750 {
751         const char *cp;
752         int cnt;
753         mmfile_t file_o;
754         struct patch *patch;
755         int i, plno, tlno;
756
757         cp = nth_line(sb, ent->lno);
758         file_o.ptr = (char*) cp;
759         cnt = ent->num_lines;
760
761         while (cnt && cp < sb->final_buf + sb->final_buf_size) {
762                 if (*cp++ == '\n')
763                         cnt--;
764         }
765         file_o.size = cp - file_o.ptr;
766
767         patch = compare_buffer(file_p, &file_o, 1);
768
769         memset(split, 0, sizeof(struct blame_entry [3]));
770         plno = tlno = 0;
771         for (i = 0; i < patch->num; i++) {
772                 struct chunk *chunk = &patch->chunks[i];
773
774                 /* tlno to chunk->same are the same as ent */
775                 if (ent->num_lines <= tlno)
776                         break;
777                 if (tlno < chunk->same) {
778                         struct blame_entry this[3];
779                         split_overlap(this, ent,
780                                       tlno + ent->s_lno, plno,
781                                       chunk->same + ent->s_lno,
782                                       parent);
783                         copy_split_if_better(sb, split, this);
784                         decref_split(this);
785                 }
786                 plno = chunk->p_next;
787                 tlno = chunk->t_next;
788         }
789         free_patch(patch);
790 }
791
792 static int find_move_in_parent(struct scoreboard *sb,
793                                struct origin *target,
794                                struct origin *parent)
795 {
796         int last_in_target, made_progress;
797         struct blame_entry *e, split[3];
798         mmfile_t file_p;
799
800         last_in_target = find_last_in_target(sb, target);
801         if (last_in_target < 0)
802                 return 1; /* nothing remains for this target */
803
804         fill_origin_blob(parent, &file_p);
805         if (!file_p.ptr)
806                 return 0;
807
808         made_progress = 1;
809         while (made_progress) {
810                 made_progress = 0;
811                 for (e = sb->ent; e; e = e->next) {
812                         if (e->guilty || cmp_suspect(e->suspect, target))
813                                 continue;
814                         find_copy_in_blob(sb, e, parent, split, &file_p);
815                         if (split[1].suspect &&
816                             blame_move_score < ent_score(sb, &split[1])) {
817                                 split_blame(sb, split, e);
818                                 made_progress = 1;
819                         }
820                         decref_split(split);
821                 }
822         }
823         return 0;
824 }
825
826
827 struct blame_list {
828         struct blame_entry *ent;
829         struct blame_entry split[3];
830 };
831
832 static struct blame_list *setup_blame_list(struct scoreboard *sb,
833                                            struct origin *target,
834                                            int *num_ents_p)
835 {
836         struct blame_entry *e;
837         int num_ents, i;
838         struct blame_list *blame_list = NULL;
839
840         /* Count the number of entries the target is suspected for,
841          * and prepare a list of entry and the best split.
842          */
843         for (e = sb->ent, num_ents = 0; e; e = e->next)
844                 if (!e->guilty && !cmp_suspect(e->suspect, target))
845                         num_ents++;
846         if (num_ents) {
847                 blame_list = xcalloc(num_ents, sizeof(struct blame_list));
848                 for (e = sb->ent, i = 0; e; e = e->next)
849                         if (!e->guilty && !cmp_suspect(e->suspect, target))
850                                 blame_list[i++].ent = e;
851         }
852         *num_ents_p = num_ents;
853         return blame_list;
854 }
855
856 static int find_copy_in_parent(struct scoreboard *sb,
857                                struct origin *target,
858                                struct commit *parent,
859                                struct origin *porigin,
860                                int opt)
861 {
862         struct diff_options diff_opts;
863         const char *paths[1];
864         int i, j;
865         int retval;
866         struct blame_list *blame_list;
867         int num_ents;
868
869         blame_list = setup_blame_list(sb, target, &num_ents);
870         if (!blame_list)
871                 return 1; /* nothing remains for this target */
872
873         diff_setup(&diff_opts);
874         diff_opts.recursive = 1;
875         diff_opts.output_format = DIFF_FORMAT_NO_OUTPUT;
876
877         paths[0] = NULL;
878         diff_tree_setup_paths(paths, &diff_opts);
879         if (diff_setup_done(&diff_opts) < 0)
880                 die("diff-setup");
881
882         /* Try "find copies harder" on new path if requested;
883          * we do not want to use diffcore_rename() actually to
884          * match things up; find_copies_harder is set only to
885          * force diff_tree_sha1() to feed all filepairs to diff_queue,
886          * and this code needs to be after diff_setup_done(), which
887          * usually makes find-copies-harder imply copy detection.
888          */
889         if ((opt & PICKAXE_BLAME_COPY_HARDER) &&
890             (!porigin || strcmp(target->path, porigin->path)))
891                 diff_opts.find_copies_harder = 1;
892
893         diff_tree_sha1(parent->tree->object.sha1,
894                        target->commit->tree->object.sha1,
895                        "", &diff_opts);
896
897         if (!diff_opts.find_copies_harder)
898                 diffcore_std(&diff_opts);
899
900         retval = 0;
901         while (1) {
902                 int made_progress = 0;
903
904                 for (i = 0; i < diff_queued_diff.nr; i++) {
905                         struct diff_filepair *p = diff_queued_diff.queue[i];
906                         struct origin *norigin;
907                         mmfile_t file_p;
908                         struct blame_entry this[3];
909
910                         if (!DIFF_FILE_VALID(p->one))
911                                 continue; /* does not exist in parent */
912                         if (porigin && !strcmp(p->one->path, porigin->path))
913                                 /* find_move already dealt with this path */
914                                 continue;
915
916                         norigin = get_origin(sb, parent, p->one->path);
917                         hashcpy(norigin->blob_sha1, p->one->sha1);
918                         fill_origin_blob(norigin, &file_p);
919                         if (!file_p.ptr)
920                                 continue;
921
922                         for (j = 0; j < num_ents; j++) {
923                                 find_copy_in_blob(sb, blame_list[j].ent,
924                                                   norigin, this, &file_p);
925                                 copy_split_if_better(sb, blame_list[j].split,
926                                                      this);
927                                 decref_split(this);
928                         }
929                         origin_decref(norigin);
930                 }
931
932                 for (j = 0; j < num_ents; j++) {
933                         struct blame_entry *split = blame_list[j].split;
934                         if (split[1].suspect &&
935                             blame_copy_score < ent_score(sb, &split[1])) {
936                                 split_blame(sb, split, blame_list[j].ent);
937                                 made_progress = 1;
938                         }
939                         decref_split(split);
940                 }
941                 free(blame_list);
942
943                 if (!made_progress)
944                         break;
945                 blame_list = setup_blame_list(sb, target, &num_ents);
946                 if (!blame_list) {
947                         retval = 1;
948                         break;
949                 }
950         }
951         diff_flush(&diff_opts);
952
953         return retval;
954 }
955
956 /* The blobs of origin and porigin exactly match, so everything
957  * origin is suspected for can be blamed on the parent.
958  */
959 static void pass_whole_blame(struct scoreboard *sb,
960                              struct origin *origin, struct origin *porigin)
961 {
962         struct blame_entry *e;
963
964         if (!porigin->file.ptr && origin->file.ptr) {
965                 /* Steal its file */
966                 porigin->file = origin->file;
967                 origin->file.ptr = NULL;
968         }
969         for (e = sb->ent; e; e = e->next) {
970                 if (cmp_suspect(e->suspect, origin))
971                         continue;
972                 origin_incref(porigin);
973                 origin_decref(e->suspect);
974                 e->suspect = porigin;
975         }
976 }
977
978 #define MAXPARENT 16
979
980 static void pass_blame(struct scoreboard *sb, struct origin *origin, int opt)
981 {
982         int i, pass;
983         struct commit *commit = origin->commit;
984         struct commit_list *parent;
985         struct origin *parent_origin[MAXPARENT], *porigin;
986
987         memset(parent_origin, 0, sizeof(parent_origin));
988
989         /* The first pass looks for unrenamed path to optimize for
990          * common cases, then we look for renames in the second pass.
991          */
992         for (pass = 0; pass < 2; pass++) {
993                 struct origin *(*find)(struct scoreboard *,
994                                        struct commit *, struct origin *);
995                 find = pass ? find_rename : find_origin;
996
997                 for (i = 0, parent = commit->parents;
998                      i < MAXPARENT && parent;
999                      parent = parent->next, i++) {
1000                         struct commit *p = parent->item;
1001                         int j, same;
1002
1003                         if (parent_origin[i])
1004                                 continue;
1005                         if (parse_commit(p))
1006                                 continue;
1007                         porigin = find(sb, p, origin);
1008                         if (!porigin)
1009                                 continue;
1010                         if (!hashcmp(porigin->blob_sha1, origin->blob_sha1)) {
1011                                 pass_whole_blame(sb, origin, porigin);
1012                                 origin_decref(porigin);
1013                                 goto finish;
1014                         }
1015                         for (j = same = 0; j < i; j++)
1016                                 if (parent_origin[j] &&
1017                                     !hashcmp(parent_origin[j]->blob_sha1,
1018                                              porigin->blob_sha1)) {
1019                                         same = 1;
1020                                         break;
1021                                 }
1022                         if (!same)
1023                                 parent_origin[i] = porigin;
1024                         else
1025                                 origin_decref(porigin);
1026                 }
1027         }
1028
1029         num_commits++;
1030         for (i = 0, parent = commit->parents;
1031              i < MAXPARENT && parent;
1032              parent = parent->next, i++) {
1033                 struct origin *porigin = parent_origin[i];
1034                 if (!porigin)
1035                         continue;
1036                 if (pass_blame_to_parent(sb, origin, porigin))
1037                         goto finish;
1038         }
1039
1040         /*
1041          * Optionally run "miff" to find moves in parents' files here.
1042          */
1043         if (opt & PICKAXE_BLAME_MOVE)
1044                 for (i = 0, parent = commit->parents;
1045                      i < MAXPARENT && parent;
1046                      parent = parent->next, i++) {
1047                         struct origin *porigin = parent_origin[i];
1048                         if (!porigin)
1049                                 continue;
1050                         if (find_move_in_parent(sb, origin, porigin))
1051                                 goto finish;
1052                 }
1053
1054         /*
1055          * Optionally run "ciff" to find copies from parents' files here.
1056          */
1057         if (opt & PICKAXE_BLAME_COPY)
1058                 for (i = 0, parent = commit->parents;
1059                      i < MAXPARENT && parent;
1060                      parent = parent->next, i++) {
1061                         struct origin *porigin = parent_origin[i];
1062                         if (find_copy_in_parent(sb, origin, parent->item,
1063                                                 porigin, opt))
1064                                 goto finish;
1065                 }
1066
1067  finish:
1068         for (i = 0; i < MAXPARENT; i++)
1069                 origin_decref(parent_origin[i]);
1070 }
1071
1072 static void assign_blame(struct scoreboard *sb, struct rev_info *revs, int opt)
1073 {
1074         while (1) {
1075                 struct blame_entry *ent;
1076                 struct commit *commit;
1077                 struct origin *suspect = NULL;
1078
1079                 /* find one suspect to break down */
1080                 for (ent = sb->ent; !suspect && ent; ent = ent->next)
1081                         if (!ent->guilty)
1082                                 suspect = ent->suspect;
1083                 if (!suspect)
1084                         return; /* all done */
1085
1086                 origin_incref(suspect);
1087                 commit = suspect->commit;
1088                 if (!commit->object.parsed)
1089                         parse_commit(commit);
1090                 if (!(commit->object.flags & UNINTERESTING) &&
1091                     !(revs->max_age != -1 && commit->date  < revs->max_age))
1092                         pass_blame(sb, suspect, opt);
1093
1094                 /* Take responsibility for the remaining entries */
1095                 for (ent = sb->ent; ent; ent = ent->next)
1096                         if (!cmp_suspect(ent->suspect, suspect))
1097                                 ent->guilty = 1;
1098                 origin_decref(suspect);
1099
1100                 if (DEBUG) /* sanity */
1101                         sanity_check_refcnt(sb);
1102         }
1103 }
1104
1105 static const char *format_time(unsigned long time, const char *tz_str,
1106                                int show_raw_time)
1107 {
1108         static char time_buf[128];
1109         time_t t = time;
1110         int minutes, tz;
1111         struct tm *tm;
1112
1113         if (show_raw_time) {
1114                 sprintf(time_buf, "%lu %s", time, tz_str);
1115                 return time_buf;
1116         }
1117
1118         tz = atoi(tz_str);
1119         minutes = tz < 0 ? -tz : tz;
1120         minutes = (minutes / 100)*60 + (minutes % 100);
1121         minutes = tz < 0 ? -minutes : minutes;
1122         t = time + minutes * 60;
1123         tm = gmtime(&t);
1124
1125         strftime(time_buf, sizeof(time_buf), "%Y-%m-%d %H:%M:%S ", tm);
1126         strcat(time_buf, tz_str);
1127         return time_buf;
1128 }
1129
1130 struct commit_info
1131 {
1132         char *author;
1133         char *author_mail;
1134         unsigned long author_time;
1135         char *author_tz;
1136
1137         /* filled only when asked for details */
1138         char *committer;
1139         char *committer_mail;
1140         unsigned long committer_time;
1141         char *committer_tz;
1142
1143         char *summary;
1144 };
1145
1146 static void get_ac_line(const char *inbuf, const char *what,
1147                         int bufsz, char *person, char **mail,
1148                         unsigned long *time, char **tz)
1149 {
1150         int len;
1151         char *tmp, *endp;
1152
1153         tmp = strstr(inbuf, what);
1154         if (!tmp)
1155                 goto error_out;
1156         tmp += strlen(what);
1157         endp = strchr(tmp, '\n');
1158         if (!endp)
1159                 len = strlen(tmp);
1160         else
1161                 len = endp - tmp;
1162         if (bufsz <= len) {
1163         error_out:
1164                 /* Ugh */
1165                 person = *mail = *tz = "(unknown)";
1166                 *time = 0;
1167                 return;
1168         }
1169         memcpy(person, tmp, len);
1170
1171         tmp = person;
1172         tmp += len;
1173         *tmp = 0;
1174         while (*tmp != ' ')
1175                 tmp--;
1176         *tz = tmp+1;
1177
1178         *tmp = 0;
1179         while (*tmp != ' ')
1180                 tmp--;
1181         *time = strtoul(tmp, NULL, 10);
1182
1183         *tmp = 0;
1184         while (*tmp != ' ')
1185                 tmp--;
1186         *mail = tmp + 1;
1187         *tmp = 0;
1188 }
1189
1190 static void get_commit_info(struct commit *commit,
1191                             struct commit_info *ret,
1192                             int detailed)
1193 {
1194         int len;
1195         char *tmp, *endp;
1196         static char author_buf[1024];
1197         static char committer_buf[1024];
1198         static char summary_buf[1024];
1199
1200         /* We've operated without save_commit_buffer, so
1201          * we now need to populate them for output.
1202          */
1203         if (!commit->buffer) {
1204                 char type[20];
1205                 unsigned long size;
1206                 commit->buffer =
1207                         read_sha1_file(commit->object.sha1, type, &size);
1208         }
1209         ret->author = author_buf;
1210         get_ac_line(commit->buffer, "\nauthor ",
1211                     sizeof(author_buf), author_buf, &ret->author_mail,
1212                     &ret->author_time, &ret->author_tz);
1213
1214         if (!detailed)
1215                 return;
1216
1217         ret->committer = committer_buf;
1218         get_ac_line(commit->buffer, "\ncommitter ",
1219                     sizeof(committer_buf), committer_buf, &ret->committer_mail,
1220                     &ret->committer_time, &ret->committer_tz);
1221
1222         ret->summary = summary_buf;
1223         tmp = strstr(commit->buffer, "\n\n");
1224         if (!tmp) {
1225         error_out:
1226                 sprintf(summary_buf, "(%s)", sha1_to_hex(commit->object.sha1));
1227                 return;
1228         }
1229         tmp += 2;
1230         endp = strchr(tmp, '\n');
1231         if (!endp)
1232                 goto error_out;
1233         len = endp - tmp;
1234         if (len >= sizeof(summary_buf))
1235                 goto error_out;
1236         memcpy(summary_buf, tmp, len);
1237         summary_buf[len] = 0;
1238 }
1239
1240 #define OUTPUT_ANNOTATE_COMPAT  001
1241 #define OUTPUT_LONG_OBJECT_NAME 002
1242 #define OUTPUT_RAW_TIMESTAMP    004
1243 #define OUTPUT_PORCELAIN        010
1244 #define OUTPUT_SHOW_NAME        020
1245 #define OUTPUT_SHOW_NUMBER      040
1246 #define OUTPUT_SHOW_SCORE      0100
1247
1248 static void emit_porcelain(struct scoreboard *sb, struct blame_entry *ent)
1249 {
1250         int cnt;
1251         const char *cp;
1252         struct origin *suspect = ent->suspect;
1253         char hex[41];
1254
1255         strcpy(hex, sha1_to_hex(suspect->commit->object.sha1));
1256         printf("%s%c%d %d %d\n",
1257                hex,
1258                ent->guilty ? ' ' : '*', // purely for debugging
1259                ent->s_lno + 1,
1260                ent->lno + 1,
1261                ent->num_lines);
1262         if (!(suspect->commit->object.flags & METAINFO_SHOWN)) {
1263                 struct commit_info ci;
1264                 suspect->commit->object.flags |= METAINFO_SHOWN;
1265                 get_commit_info(suspect->commit, &ci, 1);
1266                 printf("author %s\n", ci.author);
1267                 printf("author-mail %s\n", ci.author_mail);
1268                 printf("author-time %lu\n", ci.author_time);
1269                 printf("author-tz %s\n", ci.author_tz);
1270                 printf("committer %s\n", ci.committer);
1271                 printf("committer-mail %s\n", ci.committer_mail);
1272                 printf("committer-time %lu\n", ci.committer_time);
1273                 printf("committer-tz %s\n", ci.committer_tz);
1274                 printf("filename %s\n", suspect->path);
1275                 printf("summary %s\n", ci.summary);
1276         }
1277         else if (suspect->commit->object.flags & MORE_THAN_ONE_PATH)
1278                 printf("filename %s\n", suspect->path);
1279
1280         cp = nth_line(sb, ent->lno);
1281         for (cnt = 0; cnt < ent->num_lines; cnt++) {
1282                 char ch;
1283                 if (cnt)
1284                         printf("%s %d %d\n", hex,
1285                                ent->s_lno + 1 + cnt,
1286                                ent->lno + 1 + cnt);
1287                 putchar('\t');
1288                 do {
1289                         ch = *cp++;
1290                         putchar(ch);
1291                 } while (ch != '\n' &&
1292                          cp < sb->final_buf + sb->final_buf_size);
1293         }
1294 }
1295
1296 static void emit_other(struct scoreboard *sb, struct blame_entry *ent, int opt)
1297 {
1298         int cnt;
1299         const char *cp;
1300         struct origin *suspect = ent->suspect;
1301         struct commit_info ci;
1302         char hex[41];
1303         int show_raw_time = !!(opt & OUTPUT_RAW_TIMESTAMP);
1304
1305         get_commit_info(suspect->commit, &ci, 1);
1306         strcpy(hex, sha1_to_hex(suspect->commit->object.sha1));
1307
1308         cp = nth_line(sb, ent->lno);
1309         for (cnt = 0; cnt < ent->num_lines; cnt++) {
1310                 char ch;
1311
1312                 printf("%.*s", (opt & OUTPUT_LONG_OBJECT_NAME) ? 40 : 8, hex);
1313                 if (opt & OUTPUT_ANNOTATE_COMPAT)
1314                         printf("\t(%10s\t%10s\t%d)", ci.author,
1315                                format_time(ci.author_time, ci.author_tz,
1316                                            show_raw_time),
1317                                ent->lno + 1 + cnt);
1318                 else {
1319                         if (opt & OUTPUT_SHOW_SCORE)
1320                                 printf(" %*d %02d",
1321                                        max_score_digits, ent->score,
1322                                        ent->suspect->refcnt);
1323                         if (opt & OUTPUT_SHOW_NAME)
1324                                 printf(" %-*.*s", longest_file, longest_file,
1325                                        suspect->path);
1326                         if (opt & OUTPUT_SHOW_NUMBER)
1327                                 printf(" %*d", max_orig_digits,
1328                                        ent->s_lno + 1 + cnt);
1329                         printf(" (%-*.*s %10s %*d) ",
1330                                longest_author, longest_author, ci.author,
1331                                format_time(ci.author_time, ci.author_tz,
1332                                            show_raw_time),
1333                                max_digits, ent->lno + 1 + cnt);
1334                 }
1335                 do {
1336                         ch = *cp++;
1337                         putchar(ch);
1338                 } while (ch != '\n' &&
1339                          cp < sb->final_buf + sb->final_buf_size);
1340         }
1341 }
1342
1343 static void output(struct scoreboard *sb, int option)
1344 {
1345         struct blame_entry *ent;
1346
1347         if (option & OUTPUT_PORCELAIN) {
1348                 for (ent = sb->ent; ent; ent = ent->next) {
1349                         struct blame_entry *oth;
1350                         struct origin *suspect = ent->suspect;
1351                         struct commit *commit = suspect->commit;
1352                         if (commit->object.flags & MORE_THAN_ONE_PATH)
1353                                 continue;
1354                         for (oth = ent->next; oth; oth = oth->next) {
1355                                 if ((oth->suspect->commit != commit) ||
1356                                     !strcmp(oth->suspect->path, suspect->path))
1357                                         continue;
1358                                 commit->object.flags |= MORE_THAN_ONE_PATH;
1359                                 break;
1360                         }
1361                 }
1362         }
1363
1364         for (ent = sb->ent; ent; ent = ent->next) {
1365                 if (option & OUTPUT_PORCELAIN)
1366                         emit_porcelain(sb, ent);
1367                 else {
1368                         emit_other(sb, ent, option);
1369                 }
1370         }
1371 }
1372
1373 static int prepare_lines(struct scoreboard *sb)
1374 {
1375         const char *buf = sb->final_buf;
1376         unsigned long len = sb->final_buf_size;
1377         int num = 0, incomplete = 0, bol = 1;
1378
1379         if (len && buf[len-1] != '\n')
1380                 incomplete++; /* incomplete line at the end */
1381         while (len--) {
1382                 if (bol) {
1383                         sb->lineno = xrealloc(sb->lineno,
1384                                               sizeof(int* ) * (num + 1));
1385                         sb->lineno[num] = buf - sb->final_buf;
1386                         bol = 0;
1387                 }
1388                 if (*buf++ == '\n') {
1389                         num++;
1390                         bol = 1;
1391                 }
1392         }
1393         sb->lineno = xrealloc(sb->lineno,
1394                               sizeof(int* ) * (num + incomplete + 1));
1395         sb->lineno[num + incomplete] = buf - sb->final_buf;
1396         sb->num_lines = num + incomplete;
1397         return sb->num_lines;
1398 }
1399
1400 static int read_ancestry(const char *graft_file)
1401 {
1402         FILE *fp = fopen(graft_file, "r");
1403         char buf[1024];
1404         if (!fp)
1405                 return -1;
1406         while (fgets(buf, sizeof(buf), fp)) {
1407                 /* The format is just "Commit Parent1 Parent2 ...\n" */
1408                 int len = strlen(buf);
1409                 struct commit_graft *graft = read_graft_line(buf, len);
1410                 if (graft)
1411                         register_commit_graft(graft, 0);
1412         }
1413         fclose(fp);
1414         return 0;
1415 }
1416
1417 static int lineno_width(int lines)
1418 {
1419         int i, width;
1420
1421         for (width = 1, i = 10; i <= lines + 1; width++)
1422                 i *= 10;
1423         return width;
1424 }
1425
1426 static void find_alignment(struct scoreboard *sb, int *option)
1427 {
1428         int longest_src_lines = 0;
1429         int longest_dst_lines = 0;
1430         unsigned largest_score = 0;
1431         struct blame_entry *e;
1432
1433         for (e = sb->ent; e; e = e->next) {
1434                 struct origin *suspect = e->suspect;
1435                 struct commit_info ci;
1436                 int num;
1437
1438                 if (strcmp(suspect->path, sb->path))
1439                         *option |= OUTPUT_SHOW_NAME;
1440                 num = strlen(suspect->path);
1441                 if (longest_file < num)
1442                         longest_file = num;
1443                 if (!(suspect->commit->object.flags & METAINFO_SHOWN)) {
1444                         suspect->commit->object.flags |= METAINFO_SHOWN;
1445                         get_commit_info(suspect->commit, &ci, 1);
1446                         num = strlen(ci.author);
1447                         if (longest_author < num)
1448                                 longest_author = num;
1449                 }
1450                 num = e->s_lno + e->num_lines;
1451                 if (longest_src_lines < num)
1452                         longest_src_lines = num;
1453                 num = e->lno + e->num_lines;
1454                 if (longest_dst_lines < num)
1455                         longest_dst_lines = num;
1456                 if (largest_score < ent_score(sb, e))
1457                         largest_score = ent_score(sb, e);
1458         }
1459         max_orig_digits = lineno_width(longest_src_lines);
1460         max_digits = lineno_width(longest_dst_lines);
1461         max_score_digits = lineno_width(largest_score);
1462 }
1463
1464 static void sanity_check_refcnt(struct scoreboard *sb)
1465 {
1466         int baa = 0;
1467         struct blame_entry *ent;
1468
1469         for (ent = sb->ent; ent; ent = ent->next) {
1470                 /* Nobody should have zero or negative refcnt */
1471                 if (ent->suspect->refcnt <= 0) {
1472                         fprintf(stderr, "%s in %s has negative refcnt %d\n",
1473                                 ent->suspect->path,
1474                                 sha1_to_hex(ent->suspect->commit->object.sha1),
1475                                 ent->suspect->refcnt);
1476                         baa = 1;
1477                 }
1478         }
1479         for (ent = sb->ent; ent; ent = ent->next) {
1480                 /* Mark the ones that haven't been checked */
1481                 if (0 < ent->suspect->refcnt)
1482                         ent->suspect->refcnt = -ent->suspect->refcnt;
1483         }
1484         for (ent = sb->ent; ent; ent = ent->next) {
1485                 /* then pick each and see if they have the the correct
1486                  * refcnt.
1487                  */
1488                 int found;
1489                 struct blame_entry *e;
1490                 struct origin *suspect = ent->suspect;
1491
1492                 if (0 < suspect->refcnt)
1493                         continue;
1494                 suspect->refcnt = -suspect->refcnt; /* Unmark */
1495                 for (found = 0, e = sb->ent; e; e = e->next) {
1496                         if (e->suspect != suspect)
1497                                 continue;
1498                         found++;
1499                 }
1500                 if (suspect->refcnt != found) {
1501                         fprintf(stderr, "%s in %s has refcnt %d, not %d\n",
1502                                 ent->suspect->path,
1503                                 sha1_to_hex(ent->suspect->commit->object.sha1),
1504                                 ent->suspect->refcnt, found);
1505                         baa = 2;
1506                 }
1507         }
1508         if (baa) {
1509                 int opt = 0160;
1510                 find_alignment(sb, &opt);
1511                 output(sb, opt);
1512                 die("Baa %d!", baa);
1513         }
1514 }
1515
1516 static int has_path_in_work_tree(const char *path)
1517 {
1518         struct stat st;
1519         return !lstat(path, &st);
1520 }
1521
1522 static unsigned parse_score(const char *arg)
1523 {
1524         char *end;
1525         unsigned long score = strtoul(arg, &end, 10);
1526         if (*end)
1527                 return 0;
1528         return score;
1529 }
1530
1531 static const char *add_prefix(const char *prefix, const char *path)
1532 {
1533         if (!prefix || !prefix[0])
1534                 return path;
1535         return prefix_path(prefix, strlen(prefix), path);
1536 }
1537
1538 static const char *parse_loc(const char *spec,
1539                              struct scoreboard *sb, long lno,
1540                              long begin, long *ret)
1541 {
1542         char *term;
1543         const char *line;
1544         long num;
1545         int reg_error;
1546         regex_t regexp;
1547         regmatch_t match[1];
1548
1549         /* Allow "-L <something>,+20" to mean starting at <something>
1550          * for 20 lines, or "-L <something>,-5" for 5 lines ending at
1551          * <something>.
1552          */
1553         if (1 < begin && (spec[0] == '+' || spec[0] == '-')) {
1554                 num = strtol(spec + 1, &term, 10);
1555                 if (term != spec + 1) {
1556                         if (spec[0] == '-')
1557                                 num = 0 - num;
1558                         if (0 < num)
1559                                 *ret = begin + num - 2;
1560                         else if (!num)
1561                                 *ret = begin;
1562                         else
1563                                 *ret = begin + num;
1564                         return term;
1565                 }
1566                 return spec;
1567         }
1568         num = strtol(spec, &term, 10);
1569         if (term != spec) {
1570                 *ret = num;
1571                 return term;
1572         }
1573         if (spec[0] != '/')
1574                 return spec;
1575
1576         /* it could be a regexp of form /.../ */
1577         for (term = (char*) spec + 1; *term && *term != '/'; term++) {
1578                 if (*term == '\\')
1579                         term++;
1580         }
1581         if (*term != '/')
1582                 return spec;
1583
1584         /* try [spec+1 .. term-1] as regexp */
1585         *term = 0;
1586         begin--; /* input is in human terms */
1587         line = nth_line(sb, begin);
1588
1589         if (!(reg_error = regcomp(&regexp, spec + 1, REG_NEWLINE)) &&
1590             !(reg_error = regexec(&regexp, line, 1, match, 0))) {
1591                 const char *cp = line + match[0].rm_so;
1592                 const char *nline;
1593
1594                 while (begin++ < lno) {
1595                         nline = nth_line(sb, begin);
1596                         if (line <= cp && cp < nline)
1597                                 break;
1598                         line = nline;
1599                 }
1600                 *ret = begin;
1601                 regfree(&regexp);
1602                 *term++ = '/';
1603                 return term;
1604         }
1605         else {
1606                 char errbuf[1024];
1607                 regerror(reg_error, &regexp, errbuf, 1024);
1608                 die("-L parameter '%s': %s", spec + 1, errbuf);
1609         }
1610 }
1611
1612 static void prepare_blame_range(struct scoreboard *sb,
1613                                 const char *bottomtop,
1614                                 long lno,
1615                                 long *bottom, long *top)
1616 {
1617         const char *term;
1618
1619         term = parse_loc(bottomtop, sb, lno, 1, bottom);
1620         if (*term == ',') {
1621                 term = parse_loc(term + 1, sb, lno, *bottom + 1, top);
1622                 if (*term)
1623                         usage(blame_usage);
1624         }
1625         if (*term)
1626                 usage(blame_usage);
1627 }
1628
1629 int cmd_blame(int argc, const char **argv, const char *prefix)
1630 {
1631         struct rev_info revs;
1632         const char *path;
1633         struct scoreboard sb;
1634         struct origin *o;
1635         struct blame_entry *ent;
1636         int i, seen_dashdash, unk, opt;
1637         long bottom, top, lno;
1638         int output_option = 0;
1639         const char *revs_file = NULL;
1640         const char *final_commit_name = NULL;
1641         char type[10];
1642         const char *bottomtop = NULL;
1643
1644         save_commit_buffer = 0;
1645
1646         opt = 0;
1647         seen_dashdash = 0;
1648         for (unk = i = 1; i < argc; i++) {
1649                 const char *arg = argv[i];
1650                 if (*arg != '-')
1651                         break;
1652                 else if (!strcmp("-c", arg))
1653                         output_option |= OUTPUT_ANNOTATE_COMPAT;
1654                 else if (!strcmp("-t", arg))
1655                         output_option |= OUTPUT_RAW_TIMESTAMP;
1656                 else if (!strcmp("-l", arg))
1657                         output_option |= OUTPUT_LONG_OBJECT_NAME;
1658                 else if (!strcmp("-S", arg) && ++i < argc)
1659                         revs_file = argv[i];
1660                 else if (!strncmp("-M", arg, 2)) {
1661                         opt |= PICKAXE_BLAME_MOVE;
1662                         blame_move_score = parse_score(arg+2);
1663                 }
1664                 else if (!strncmp("-C", arg, 2)) {
1665                         if (opt & PICKAXE_BLAME_COPY)
1666                                 opt |= PICKAXE_BLAME_COPY_HARDER;
1667                         opt |= PICKAXE_BLAME_COPY | PICKAXE_BLAME_MOVE;
1668                         blame_copy_score = parse_score(arg+2);
1669                 }
1670                 else if (!strncmp("-L", arg, 2)) {
1671                         if (!arg[2]) {
1672                                 if (++i >= argc)
1673                                         usage(blame_usage);
1674                                 arg = argv[i];
1675                         }
1676                         else
1677                                 arg += 2;
1678                         if (bottomtop)
1679                                 die("More than one '-L n,m' option given");
1680                         bottomtop = arg;
1681                 }
1682                 else if (!strcmp("--score-debug", arg))
1683                         output_option |= OUTPUT_SHOW_SCORE;
1684                 else if (!strcmp("-f", arg) ||
1685                          !strcmp("--show-name", arg))
1686                         output_option |= OUTPUT_SHOW_NAME;
1687                 else if (!strcmp("-n", arg) ||
1688                          !strcmp("--show-number", arg))
1689                         output_option |= OUTPUT_SHOW_NUMBER;
1690                 else if (!strcmp("-p", arg) ||
1691                          !strcmp("--porcelain", arg))
1692                         output_option |= OUTPUT_PORCELAIN;
1693                 else if (!strcmp("--", arg)) {
1694                         seen_dashdash = 1;
1695                         i++;
1696                         break;
1697                 }
1698                 else
1699                         argv[unk++] = arg;
1700         }
1701
1702         if (!blame_move_score)
1703                 blame_move_score = BLAME_DEFAULT_MOVE_SCORE;
1704         if (!blame_copy_score)
1705                 blame_copy_score = BLAME_DEFAULT_COPY_SCORE;
1706
1707         /* We have collected options unknown to us in argv[1..unk]
1708          * which are to be passed to revision machinery if we are
1709          * going to do the "bottom" procesing.
1710          *
1711          * The remaining are:
1712          *
1713          * (1) if seen_dashdash, its either
1714          *     "-options -- <path>" or
1715          *     "-options -- <path> <rev>".
1716          *     but the latter is allowed only if there is no
1717          *     options that we passed to revision machinery.
1718          *
1719          * (2) otherwise, we may have "--" somewhere later and
1720          *     might be looking at the first one of multiple 'rev'
1721          *     parameters (e.g. " master ^next ^maint -- path").
1722          *     See if there is a dashdash first, and give the
1723          *     arguments before that to revision machinery.
1724          *     After that there must be one 'path'.
1725          *
1726          * (3) otherwise, its one of the three:
1727          *     "-options <path> <rev>"
1728          *     "-options <rev> <path>"
1729          *     "-options <path>"
1730          *     but again the first one is allowed only if
1731          *     there is no options that we passed to revision
1732          *     machinery.
1733          */
1734
1735         if (seen_dashdash) {
1736                 /* (1) */
1737                 if (argc <= i)
1738                         usage(blame_usage);
1739                 path = add_prefix(prefix, argv[i]);
1740                 if (i + 1 == argc - 1) {
1741                         if (unk != 1)
1742                                 usage(blame_usage);
1743                         argv[unk++] = argv[i + 1];
1744                 }
1745                 else if (i + 1 != argc)
1746                         /* garbage at end */
1747                         usage(blame_usage);
1748         }
1749         else {
1750                 int j;
1751                 for (j = i; !seen_dashdash && j < argc; j++)
1752                         if (!strcmp(argv[j], "--"))
1753                                 seen_dashdash = j;
1754                 if (seen_dashdash) {
1755                         if (seen_dashdash + 1 != argc - 1)
1756                                 usage(blame_usage);
1757                         path = add_prefix(prefix, argv[seen_dashdash + 1]);
1758                         for (j = i; j < seen_dashdash; j++)
1759                                 argv[unk++] = argv[j];
1760                 }
1761                 else {
1762                         /* (3) */
1763                         path = add_prefix(prefix, argv[i]);
1764                         if (i + 1 == argc - 1) {
1765                                 final_commit_name = argv[i + 1];
1766
1767                                 /* if (unk == 1) we could be getting
1768                                  * old-style
1769                                  */
1770                                 if (unk == 1 && !has_path_in_work_tree(path)) {
1771                                         path = add_prefix(prefix, argv[i + 1]);
1772                                         final_commit_name = argv[i];
1773                                 }
1774                         }
1775                         else if (i != argc - 1)
1776                                 usage(blame_usage); /* garbage at end */
1777
1778                         if (!has_path_in_work_tree(path))
1779                                 die("cannot stat path %s: %s",
1780                                     path, strerror(errno));
1781                 }
1782         }
1783
1784         if (final_commit_name)
1785                 argv[unk++] = final_commit_name;
1786
1787         /* Now we got rev and path.  We do not want the path pruning
1788          * but we may want "bottom" processing.
1789          */
1790         argv[unk++] = "--"; /* terminate the rev name */
1791         argv[unk] = NULL;
1792
1793         init_revisions(&revs, NULL);
1794         setup_revisions(unk, argv, &revs, "HEAD");
1795         memset(&sb, 0, sizeof(sb));
1796
1797         /* There must be one and only one positive commit in the
1798          * revs->pending array.
1799          */
1800         for (i = 0; i < revs.pending.nr; i++) {
1801                 struct object *obj = revs.pending.objects[i].item;
1802                 if (obj->flags & UNINTERESTING)
1803                         continue;
1804                 while (obj->type == OBJ_TAG)
1805                         obj = deref_tag(obj, NULL, 0);
1806                 if (obj->type != OBJ_COMMIT)
1807                         die("Non commit %s?",
1808                             revs.pending.objects[i].name);
1809                 if (sb.final)
1810                         die("More than one commit to dig from %s and %s?",
1811                             revs.pending.objects[i].name,
1812                             final_commit_name);
1813                 sb.final = (struct commit *) obj;
1814                 final_commit_name = revs.pending.objects[i].name;
1815         }
1816
1817         if (!sb.final) {
1818                 /* "--not A B -- path" without anything positive */
1819                 unsigned char head_sha1[20];
1820
1821                 final_commit_name = "HEAD";
1822                 if (get_sha1(final_commit_name, head_sha1))
1823                         die("No such ref: HEAD");
1824                 sb.final = lookup_commit_reference(head_sha1);
1825                 add_pending_object(&revs, &(sb.final->object), "HEAD");
1826         }
1827
1828         /* If we have bottom, this will mark the ancestors of the
1829          * bottom commits we would reach while traversing as
1830          * uninteresting.
1831          */
1832         prepare_revision_walk(&revs);
1833
1834         o = get_origin(&sb, sb.final, path);
1835         if (fill_blob_sha1(o))
1836                 die("no such path %s in %s", path, final_commit_name);
1837
1838         sb.final_buf = read_sha1_file(o->blob_sha1, type, &sb.final_buf_size);
1839         num_read_blob++;
1840         lno = prepare_lines(&sb);
1841
1842         bottom = top = 0;
1843         if (bottomtop)
1844                 prepare_blame_range(&sb, bottomtop, lno, &bottom, &top);
1845         if (bottom && top && top < bottom) {
1846                 long tmp;
1847                 tmp = top; top = bottom; bottom = tmp;
1848         }
1849         if (bottom < 1)
1850                 bottom = 1;
1851         if (top < 1)
1852                 top = lno;
1853         bottom--;
1854         if (lno < top)
1855                 die("file %s has only %lu lines", path, lno);
1856
1857         ent = xcalloc(1, sizeof(*ent));
1858         ent->lno = bottom;
1859         ent->num_lines = top - bottom;
1860         ent->suspect = o;
1861         ent->s_lno = bottom;
1862
1863         sb.ent = ent;
1864         sb.path = path;
1865
1866         if (revs_file && read_ancestry(revs_file))
1867                 die("reading graft file %s failed: %s",
1868                     revs_file, strerror(errno));
1869
1870         assign_blame(&sb, &revs, opt);
1871
1872         coalesce(&sb);
1873
1874         if (!(output_option & OUTPUT_PORCELAIN))
1875                 find_alignment(&sb, &output_option);
1876
1877         output(&sb, output_option);
1878         free((void *)sb.final_buf);
1879         for (ent = sb.ent; ent; ) {
1880                 struct blame_entry *e = ent->next;
1881                 free(ent);
1882                 ent = e;
1883         }
1884
1885         if (DEBUG) {
1886                 printf("num read blob: %d\n", num_read_blob);
1887                 printf("num get patch: %d\n", num_get_patch);
1888                 printf("num commits: %d\n", num_commits);
1889         }
1890         return 0;
1891 }